Fatty acid profile, volatiles and antibacterial screening of lipids of the sponge Fasciospongia cavernosa (Schmidt) collected from the bay of Bengal (Orissa coast)

Antimicrobial Potentials of Haliclona fibulata Derived Compounds for Combatting Drug-Resistant Bacterial Infections in Zebrafish Model

The rising threat of antimicrobial resistance among pathogens highlights the critical need for novel antimicrobial agents. This study explores the potential of natural products by investigating n-hexane extracts from the marine sponge Haliclona fibulata (HF) for their antibacterial efficacy. The well diffusion method of HF extract showed significant antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus with inhibition zones of 20 ± 0.66, 27 ± 0.58, and 22 ± 0.33 mm, respectively. Scanning electron microscopy investigations confirmed the disruptive impact of the extracts on bacterial cell morphology. Further investigations using P. aeruginosa-infected zebrafish model revealed that HF treatment improved survival rates in a dose-dependent manner. Additionally, oxidative stress and apoptosis were significantly reduced in the 100 µg/mL (HF100) treatment group, alongside downregulation of inflammatory markers such as il-1β, nf-kβ, tnf-α, and inos. Histological assessments showed reduced intestinal damage and fewer circulating macrophages in HF100-treated zebrafish larvae. Identifying potent bioactive compounds within the extracts suggests that HF could be a valuable source of natural antimicrobials, warranting further exploration for developing treatments against pathogenic infections.

Comparative metabolomic analysis reveals shared and unique chemical interactions in sponge holobionts

BACKGROUND

Sponges are ancient sessile metazoans, which form with their associated microbial symbionts a complex functional unit called a holobiont. Sponges are a rich source of chemical diversity; however, there is limited knowledge of which holobiont members produce certain metabolites and how they may contribute to chemical interactions. To address this issue, we applied non-targeted liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography mass spectrometry (GC-MS) to either whole sponge tissue or fractionated microbial cells from six different, co-occurring sponge species.

RESULTS

Several metabolites were commonly found or enriched in whole sponge tissue, supporting the notion that sponge cells produce them. These include 2-methylbutyryl-carnitine, hexanoyl-carnitine and various carbohydrates, which may be potential food sources for microorganisms, as well as the antagonistic compounds hymenialdisine and eicosatrienoic acid methyl ester. Metabolites that were mostly observed or enriched in microbial cells include the antioxidant didodecyl 3,3'-thiodipropionate, the antagonistic compounds docosatetraenoic acid, and immune-suppressor phenylethylamide. This suggests that these compounds are mainly produced by the microbial members in the sponge holobiont, and are potentially either involved in inter-microbial competitions or in defenses against intruding organisms.

CONCLUSIONS

This study shows how different chemical functionality is compartmentalized between sponge hosts and their microbial symbionts and provides new insights into how chemical interactions underpin the function of sponge holobionts. Video abstract.

Anti-platelet-activating factor, antibacterial, and antiradical activities of lipids extract from silver carp brain

BACKGROUND

Epidemiological studies have verified the protective role of fish lipids in cardiovascular diseases. However, the effects of fish lipids on health boost remain undefined. Large amounts of by-products, such as fish brain which contains high level of lipids, are produced with silver carp processing. Fish brain is rich in bioactive lipids which are overwhelmingly effective in preventing cardiovascular diseases. The aim of this study was to elucidate the pharmacological activities of silver carp brain lipids against diseases by inhibiting platelet-activating factor (PAF), suppressing bacterial growth and scavenging free radicals.

METHODS

Total lipids (TL) were extracted from silver carp brain and separated into polar lipids (PL) and neutral lipids (NL). The capabilities of the lipid fractions in aggregating washed rabbit platelet or in inhibiting PAF-induced platelet aggregation were tested. Their antibacterial and antiradical activities were studied as well.

RESULTS

The lipid fractions exhibited strong inhibitory activities, and the activity of TL was mainly attributed to NL. TL exhibited antibacterial activity towards Staphylococcus aureus, while NL managed to fight against S. aureus and Escherichia coli. PL excelled TL and NL in simultaneously suppressing the growths of Shigella dysenteriae and Salmonella typhi besides those of S. aureus and E. coli. The scavenging effect of PL on 2,2-diphenyl-1-picrylhydrazyl radical was considerably higher than those of TL and NL.

CONCLUSION

The present study may help to explain the protective role of fish lipids against diseases and may be responsible for the effectiveness of fish brain in benefiting health.